12.
A solar heater uses energy from the Sun to heat water. The panels of the heater are painted black.
Why is this?

Answer:

adaptive optics

Explanation:

simple

Answer:

4V

Explanation:

First, we calculate the total resistance to the given battery cell of emf 5V. The total resistance is the sum of all the resistance in the cell i.e.

Total resistance = 2Ω + 8Ω = 10Ω

Using ohms law equation to calculate the current passing through the battery cell:

V = IR

Where; V = voltage, I = current, R = resistance

5V = I × 10Ω

I = 5/10

I = 0.5A

Terminal voltage is calculated by the us of the following equation:

V=emf−IR

Where; R is internal resistance

V = 5 - (0.5 × 2)

V = 5 - 1

V = 4V

Therefore, the potential difference across the terminals of the battery cell is 4V

Answer:

[tex]\mu=0.39[/tex]

Explanation:

From the question we are told that:

Angle [tex]\theta=28[/tex]

Acceleration [tex]a=1.25m/s^2[/tex]

Generally the equation for Frictional force  is mathematically given by

[tex]F=\muN[/tex]

Where

[tex]N=mgcos \theta[/tex]

[tex]N=mgcos 28[/tex]

Since

Friction force is acting against move of box

Therefore

[tex]mgsin(28) - 1.25m = \mu mgcos(28)[/tex]

[tex]\mu=\frac{gsin(28) - 1.25}{gcos(28)}[/tex]

[tex]\mu=0.39[/tex]

Answer:

Weight = 160 N

Explanation:

The weight of an object is a measure of the gravitational force on the object. So that weight is synonymous to the force applied by the object.

i.e Weight = mass x gravitational force

Also, the pressure of an object is the ratio of its force to area covered by the object. So that;

P = [tex]\frac{F}{A}[/tex]

Given that: area = 4 [tex]cm^{2}[/tex] (0.0004 [tex]m^{2}[/tex]), and pressure = 100 000 N[tex]m^{-2}[/tex].

Then;

F = PA

  = 100 000 N[tex]m^{-2}[/tex] x 0.0004 [tex]m^{2}[/tex]

F = 40 N

The force applied on the ground by each of the four tyres of the car is 40 N.

Thus, the weight of the car = 4 x 40 N

                                     = 160 N

Answer:

T₂ = 305.17 K

Explanation:

Given that,

Heat, Q = 6000 J

Mass, m = 200 gram

Initial temperature, T₁ = 25° C

We need to find its final temperature. Let it is T₂.

We know that,

[tex]Q=mc\Delta T[/tex]

Where

c is the specific heat of water, c = 4.18 J/g°C

So,

[tex]6000=200\times 4.18\times (T_2-298)\\\\\dfrac{6000}{200\times 4.18}=(T_2-298)\\\\7.17=(T_2-298)\\\\7.17+298=T_2\\\\T_2=305.17\ K[/tex]

So, the final temperature is equal to 305.17  K.

Answer:

35.4 cm

Explanation:

We have that when the level of mercury on either limb is the same, the pressure of the trapped air, P₁ = Atmospheric pressure

Also the initial height of the mercury in the tube = The reading of the barometer = 75.0 cm

The initial length of the air column, l₁ = 6.3 cm

The final length of the air column, l₂ = 4.2 cm (The length is expected to decrease due to compression)

The volume, V = l × A

Where;

A = The cross sectional area of the tube

Therefore, the volume of the air column is directly proportional to the length of the air column

∴ V ∝ l

According to Boyles law, we have;

P₁·V₁ = P₂·V₂

Where;

P₁ = The initial pressure in the air column before more mercury is added

V₁ = The initial volume occupied by the air in the air column

P₂, and V₂ are the final pressure and volume of the air column respectively

Given that V = l·A, we can write;

P₁·l₁·A = P₂·l₂·A

P₂ = P₁·l₁·A/(l₂·A) = P₁·l₁/(l₂) = P₁ × 6.3/4.2 = 1.5·P₁

The pressure in the air column after more mercury is added, P₂ = 1.5 × P₁

P₁ = Atmospheric pressure, therefore;

The pressure in the air column after more mercury is added, P₂ = 1.5 × Atmospheric pressure

Pressure = h·ρ·g

Where;

ρ = The density of the substance

g = The acceleration due to gravity

h = The height of the column of the fluid

Given that the density and the gravitational force, can be taken as constant, we have that the pressure of the fluid is directly proportional to the height of the fluid column

Therefore, when the pressure doubles, the height of the fluid column doubles, and when the factor of increase is 1.5, we have;

The final level of the mercury, h₂ = 1.5·h₁ = 1.5×75 cm = 112.5 cm

The initial length of the closed end of the J tube, [tex]h_{closed1}[/tex] = 6.3 cm + 75 cm = 81.3 cm

The final length of the mercury in the closed end, [tex]h_{closed2}[/tex] = 81.3 cm - 4.2 cm = 77.1 cm

The difference in the level of mercury, Δh = h₂ - [tex]h_{closed2}[/tex]

∴ Δh = 112.5 cm - 77.1 cm = 35.4 cm

The difference in the levels of mercury in the limbs, Δh = 35.4 cm

Answer:

both answer is option C

Explanation:

tag me brainliest

Answer:

The correct answer is - distress.

Explanation:

Eustress is a type of stress that is beneficial to person and caused by adrenaline. Hypostress is a stress that is caused due to boredom or no work. It is stress comes with wasting the time.

Distress is the bad stress caused by anxiety, sadness, grief, and such type of stress that is caused irritability. Irritability is caused not just by stress but many factors.

The English Bill of Rights helped to shape the colonists' views of government by promoting the ideas of individual liberty, representative democracy, and limited government.

The English Bill of Rights is a document that was passed by the Parliament of England in 1689. It was a key moment in the development of modern democratic government, as it established certain rights and protections for English citizens, such as the right to bear arms, the right to a fair trial, and the prohibition of cruel and unusual punishment.

The English Bill of Rights also limited the power of the monarchy, requiring the king or queen to obtain the consent of Parliament before levying taxes or making other important decisions. Its influence can still be seen today in many democracies around the world.

Learn more about English bill of rights, here:

https://brainly.com/question/20986147

#SPJ7

Answer:

True

Explanation:

True, atoms create electromagnetic fields that form repulsion to keep them from touching.

Direct current (DC) is the flow of electric charge in only one direction. It is the steady state of a constant-voltage circuit. Most well-known applications, however, use a time-varying voltage source. Alternating current (AC) is the flow of electric charge that periodically reverses direction.

Answer:

7.35kg

Explanation:

Hope this is helpful :)

Answer:

acceleration = - 150 m/s^2

distance = 9 miles.

Explanation:

initial speed, u = 60 mph

time, t = 12minutes = 0.2 hour

final speed, v = 30 mph

Let the acceleration is a and the distance is s.

By the first equation of motion

v = u + at

30 = 60 + a x 0.2

a = - 150 m/s^2

Let the distance is s.

Use third equation of motion is

[tex]v^2 = u^2 + 2 a s \\\\30^2 = 60^2 + 2 \times 150\times s\\\\s = 9 miles[/tex]

there u go fella hope u understood

Answer:

25 km/hr

Explanation:

Since Ali's average speed for his trip to school is u = 20 km/hr and his average speed for the return trip to back home from school is v = 30 km/hr, thus his total average speed for the journey is thus V = (initial average speed + final average speed)/2 = (u + v)/2

Substituting the values of the variables into the equation, we have

V = (u + v)/2

V = (20  km/hr + 30 km/hr)/2

V = 50 km/hr/2

V = 25 km/hr

So, the average speed for Ali's trip is 25 km/hr

Answer:

The type of image formed on a screen by a convex lens is real, enlarged and inverted.

Explanation:

A lens can be defined as a transparent optical instrument that refracts rays of light to produce a real image.

Basically, there are two (2) main types of lens and these includes;

I. Diverging (concave) lens.

II. Converging (convex) lens.

A converging lens refers to a type of lens that typically causes parallel rays of light with respect to its principal axis to come to a focus (converge) and form a real image.

Basically, the type of image formed on a screen by a converging (convex) lens is real, enlarged and inverted because it is usually thick across the middle (causing rays of light to converge) but thin at the lower and upper edges.

Answer:

Deflating the tires by pulling the valve stems

Explanation:

When an accident happens, the EMT process is to take off the top of the vehicle of the highly damaged vehicle so that it can easily be assessed to rescue the vehicle occupants. This creates a bigger exit for the rescuers to take out the people. Vehicle extrication means removing the vehicle from around someone involved in a fatal collision, when other other ways of exiting is not advised or possible. to stabilize the vehicle you have to deflate all tires by pulling the valve stems.

Answer:

Explanation:

En la historia de la ciencia se han dado auténticas barbaridades. Pruebas con animales que hoy no perdonaría nadie, o investigaciones de conducta con personas como la de la cárcel de Stanford, que se han saldado como una especie de pasado incómodo sobre los límites de la experimentación. Sin embargo, pocos se pueden acercar por su carácter perturbador al denominado experimento de Little Albert o Pequeño Albert: El salvaje intento por probar con un bebé que las fobias pueden ser condicionadas y aprendidas. Y lo que es peor, conseguirlo.

Esta idea surgió de la mente de John Broadus Watson, reconocido padre de la rama conductista de la psicología, que desde 1913 había comenzado a probar en animales sus tesis. Estas bebían directamente del los estudios de Iván Pavlov, fisiólogo ruso que ganó el Nobel en 1904 por sus estudios sobre el sistema digestivo, pero que también sentó precedentes sobre la psicología.

link por si te interesa:

https://hipertextual.com/2017/10/pequeno-albert

Answer:

shushhhgggvvv vgfxgh

Explanation:

gey laahhg

Answer:

779.87 N/m²

Explanation:

Pressure = Force (F) / Area (A)

Recall :

Force = ma ; mass * acceleration due to gravity

a = 9.8 m/s² ; mass = 0.4kg

Force, F = 0.4 * 9.8 = 3.92 N

Area = πr² ; r = Radius = 4cm = 4 / 100 = 0.04 m

Area = π0.04² = 0.0050265 m²

Hence,

Pressure = 3.92 / 0.0050265

Pressure = 779.86670 N/m²

Pressure = 779.87 N/m²

Answer:

C voltage

Explanation:

Voltage is the change in electric potential so basically current flows from high potential to low potential due to voltage.

Answer:

A

Explanation:

Answer:

Ottoman

Explanation:

siri told me after I asked

Answer:

750 N

Explanation:

the tension on the rope is the weight of the hero

Answer:

112 N at 239°

Explanation:

Applying,

Pythagoras theorem,

a² = b²+c².................. Equation 1

Where a = net force

From the question,

Given: b = 57.6 N, c = 95.7 N

Substitute into equation 1

a² = 57.6²+95.7²

a² = 3317.76+9158.49

a² = 12476.25

a = √12476.25

a = 111.7 N

a ≈ 112 N

Then the direction is given as

∅ = tan⁻¹(c/b)........... Equation 2

∅ = tan⁻¹(95.7/57.6)

∅ = tan⁻¹(1.66)

∅ = 58.9°

∅ ≈ 59°

Since the angle is in the third quadrant,

∅' = 59+180

∅ = 239°

Hence the right answer is

112 N at 239°

Answer:

A weed is a plant considered undesirable in a particular situation, "a plant in the wrong place". Examples commonly are plants unwanted in human-controlled settings, such as farm fields, gardens, lawns, and parks

Answer:

The field is parallel to the direction of flow of the current.

Answer:

Explanation:

What we are basically looking for here is how long it takes the first stone to hit the water. We have everything we need to figure that out. We will use the equation

Δx = . Filling in, we will solve for t, the time is takes the first stone to hit the water (which is the same for both since they both hit the water at the same time):

which is a quadratic that we will have to factor. Get it into standard form, setting it equal to 0:

and factor to get that

t = 3.2 s and t = -2.8 s

Since time can't ever be negative, it takes 3.2 s for the stones to hit the water.

Answer:

Stop going on peoples pages and  answering random things kid, get a life

Learn to  solve  problems instead

Explanation:

I answered this because this kid just goes on random pages, and answers incorrectly for points. Check this egirl wannabe's profile